Many types of antenna systems comprise arrays of antenna elements that each collects or emits electromagnetic radiation. For example, an array of antenna horns can be used to acquire signals in a space, airborne, or terrestrial application, such as on a satellite, an aircraft, or a fixed tower. In such applications, multiple-beam antennas have multiple feed elements that form multiple communication beams.
Disposed in an orbiting satellite, an array of receiving horns can be pointed towards the ground so that each horn has a field of reception that is centered on a different geographic area of the Earth. In this scenario, the geographic coverage of each horn overlaps the coverage of adjacent horns. That is, each horn in the array receives signals not only from a primary geographic region, but also from the reception areas of adjacent horns. The overlapping coverage often results in isolation issues between the various antenna horns. Moreover, the signals from various antenna elements can exhibit undesirable sidelobes associated with degraded isolation, interference, cross-coupling, or some other extraneous effect.
One proposed method for addressing signal degradation in antenna array applications involves extracting energy from the output line of each antenna array element and feeding that extracted energy to the output lines of adjacent antenna array elements. When applied to the output line of an adjacent antenna element, the extracted energy interacts with the signals propagating thereon to improve signal fidelity. In other words, “tapping off” a fraction of each antenna signal and adding the tapped-off signals to other antenna signals is a known technique for suppressing sidelobes. Thus, mixing the signals output by the various antenna elements can improve the quality of the individual signals.
However, the conventional technologies that are available for implementing the signal mixing are generally lacking in terms of manufacturability and therefore offer limited commercial appeal. For example, one conventional technology for handling the signals employs a complex, intertwined system of waveguide plumbing to implement signal extraction, routing, and combining. That is, conventional systems typically comprise a network of waveguide tubes that are bent and fused to cross-couple energy among one another. The waveguide plumbing typically extracts signal energy from each antenna line and divides that extracted energy among six other antenna lines so that each line is in communication with other tapped waveguides. In applications involving large arrays of antenna elements, bending and joining numerous pieces of waveguide tubing to fabricate such a complex system is often not economically feasible.
To address these representative deficiencies in the art, what is needed is an improved capability for improving isolation and suppressing sidelobes of signals associated with an antenna array or a multiple-bean antenna. Another need exists for an improved system for extracting energy or signals from an antenna output line and for feeding the extracted signals to adjacent antenna output lines. Yet another need exists for a modular and/or manufacturable system for managing signals associated with an antenna array. A capability addressing one or more of these needs would help provide signals with improved fidelity in multi-beam or multi-element antenna applications.